Oxygen Storage In Transition Metal-Doped Bixbyite Vanadium Sesquioxide Nanocrystals

Bixbyite vanadium sesquioxide (V2O3) is a metastable polymorph of vanadium oxide that has been shown to have a significant oxygen storage capacity (OSC) with very low-temperature oxidation onset. In this work, bixbyite V2O3 nanocrystals were synthesized with titanium and manganese dopants. Doped materials with varied dopant concentrations were synthesized, and all were incorporated as aliovalent metal ions. The OSC of these nanocrystal materials was evaluated over ten oxidation and reduction cycles. It was found that over these ten cycles, the OSC of all the materials fell drastically. In situ X-ray diffraction evidence shows that manganese-doped materials degrade into an amorphous manganese-containing vanadate, while titanium-doped materials form crystalline degradation products. In all cases, this degradation causes an increase in the minimum mass achieved during oxygen release, indicating irreversible oxidation.